898 



PHYSIOLOGY 



On registering the endocardiac pressure by the optical method it is 

 found that the curves vary in form according to the condition of the heart. 



FIG. 398. Endocardiac pressure tracings, taken with Piper's manometer 

 A, Simultaneous tracings from left ventricle and left auricle. To be read from left 

 to right. B and C taken from left ventricle, C at a faster rate of recording surface 

 thanB. To be read from right to left. K!= closure of A.V. valves; Si opening 



of aortic valves; S 2 , elastic oscillation or wave; K 2 , opening of A. V. valves. 



In order to interpret these curves we must utilise the knowledge obtained 

 from a simultaneous record of the pressures in the auricle and ventricle, or 

 in the ventricle and aorta. Figure 398 represents the different forms 



